Dual head for a multi-needle sewing machine

ABSTRACT

A dual head for a multi-needle machine of the type sewing a series of long (straight or zigzag) lines of stitching into an elongate sheet of bedding material passing through the machine, comprising: A. a box frame; B. frame-mounted first and second dual sewing machine heads; and C. a common means for positively driving said dual heads in a substantially fixed phase relationship. The dual sewing heads, on opposite sides of a transverse separating plane passing vertically through the box frame, comprise: (1) first and second multi-needle bars for carrying first and second successions of sewing needles; (2) first and second means for positively reciprocating the multi-needle bars vertically; (3) first and second presser-foot bars for carrying first and second successions of presser feet; (4) first and second means for positively reciprocating the presser-foot bars vertically; (5) first and second thread pull levers; and (6) first and second means for oscillating the thread pull levers. By reversely operating the first and second dual heads in 180* out-of-phase relationship, the vibrations of one head are counterbalanced by the vibrations of the other head to such an extent that it is possible to increase the operating speed in substantial measure. By positively driving each head from a common drive, they move in a fixed phase relationship so that identical sewing and presser foot operations are obtained and sewing speed, stitch-length and other related variations between heads thereby eliminated. By adjusting the angular position of the thread pull lever one way or the other, its thread pulling function can be advanced or retarded.

ilnited Mates Patent [1 1 hash [11] 3,7d9fi37 [451 an at, was

[ DUAL HEAD FOR A lWlUL'ii-NlElEllitLlE SEWHNG MACliilllNlE David R.Cash, Louisville, Ky.

[73] Assignee: James Cash Machine (30., Louisville,

22 Filed: Dec. 22, 11971 21 Appl. No; swans [75] Inventor:

Primary Examiner-Geo. V. Larlrin Attorney-Arthur 1F. Robert [5 7 1ABSTRACT A dual head for a multi-needle machine of the type sewing aseries of long (straight or zigzag) lines of stitching into an elongatesheet of bedding material passing through the machine, comprising: A. abox frame; B. frame-mounted first and second dual sewing machine heads;and C. a common means for positively driving said dual heads in asubstantially fixed phase relationship.

The dual sewing heads, on opposite sides of a transverse separatingplane passing vertically through the box frame, comprise: (1) first andsecond multi-needle bars for carrying first and second successions ofsewing needles; (2) first and second means for positively reciprocatingthe multi-needle bars vertically; (3) first and second resser-foot barsfor carrying first and second successions of presser feet; (4) first andsecond means for positively reciprocating the presser-foot barsvertically; (5) first and second thread pull levers; and (6) first andsecond means for oscillating the thread pull levers.

By reversely operating the first and second dual heads in 180out-of-phase relationship, the vibrations of one head arecounterbalanced by the vibrations of the other head to such an extentthat it is possible to increase the operating speed in substantialmeasure. By positively driving each head from a common drive, they movein a fixed phase relationship so that identical sewing and presser footoperations are obtained and sewing speed, stitch-length and otherrelated variations between heads thereby eliminated. By adjusting theangular position of the thread pull lever one way or the other, itsthread pulling function can be advanced or retarded.

9 Claims, 1165 Drawing Figures PATENIEU JUL3 1 I975 sum 3 or 3 35 FIG."36

FIG. l2

DUAL HEAD FOR A MULTll-NEEDLE SEWING MACHINE BACKGROUND OF THEINVENTION 1. Field Of The Invention This invention relates tomulti-needle machines of the type sewing a series of long parallel linesof stitching into an elongate sheet of bedding material passing throughthe machine.

2. Description Of The Prior Art 1 The Cash U.S. Pat. No. 3,192,886granted July 6, 1965 discloses a multi-needle machine of the type towhich the present invention relates. It comprises: a frame-mountedsewing means including a single multineedle bar carrying a succession ofsewing needles and means for reciprocating the multi-needle barvertically; and a single frame-ounted presser foot means including apresser-foot bar carrying a succession of presser feet and means forreciprocating the presser foot bar vertically.

Haberstump U.S. Pat. No. 2,238,773, Charles U.S. Pat. No. 3,162,155 andNowicki U.S. Pat. No. 3,249,078 likewise disclose single headmulti-needle machines.

Nowicki patent U.S. Pat. No. 3,396,687 discloses a multi-needle machinein which two needle bars are horizontally reciprocated in 180out-of-phase relationship but both needle bars reciprocate up and downtogether in the same phase relationship. Other multi-needle machineshave dual heads but employ separate and independent drives which permitstitch length (and other) variations therebetween.

SUMMARY OF THE INVENTION Objects of the Invention The principal objectof the present invention is to provide a simple improvement whichsubstantially reduces the inherent vibration and correspondingly permitsa substantial increase in production.

Another important object is to provide a dual head multi-needle sewingmachine with a simple improvement, which substantially eliminates stitchlength and other related variations between the heads.

Another desirable object is to provide an easy and simple means foradjusting the angular position of the thread pull levers one way or theother so as to correspondingly advance or retard their respective threadpulling functions.

Statement of the Invention All of the more important objectives of thepresent invention are substantially achieved by driving both heads(including the sewing heads, the pressure-foot means and the threadpulls) positively from a common drive means and in an out-of-phaserelationship closely approximating 180. The common positive drive causestheir corresponding parts to move in a fixed phase relationship, whicheliminates sewing speed, stitch length and like variations between headsand correspoindingly insures identical sewing operations with identicalresults. The 180 out-of-phase relationship causes the inherentvibrations of one head to be substantially cancelled or counter-balancedby the inherent vibrations of the other head and correspondingly permitsthe operating speed to be very substantially increased.

In conventionally constructed sewing machines, it is common practice toprovide the sewing head with a rotary operating shaft, mount acrankwheel on that shaft, provide that wheel with an offset crank orwrist pin and use a connecting rod or pitman to link that pin with thevertical reciprocating rod which carries the needle bar.

Another object of the present invention is accomplished by making theangular position of such crank or wrist pin adjustable, providing thatadjustable pin with a rigid radial link or arm and mounting the middleof the oscillating thread pull lever on the outer end por tion of thatarm. With this arrangement, the angular position (of the rigid unitformed by the wrist pin and radial arm) can be easily and quicklyadjusted one way or the other to advance or retard pull of the lever onthe sewing thread without otherwise affecting the operation of thesewing head or associated means.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiment of theinvention is illustrated in the accompanying drawings wherein:

FIG. 1 is a somewhat schematic side elevation of the base frame with itsfront end at the left;

FIG. 2 is a somewhat schematic front side elevation of the A-frame;

FIG. 3 is a perspective view of the assembled base and A-frarnes, thisview looking at a front corner of the machine with the front end of themachine and the front side of the A-frame at the left and with that sideof the base frame, which is seen in FIG. 1, at the right;

FIG. 4 is an end elevation of the drive gear end of one of the boxframes corresponding to one taken along line 4-4 of FIG. 2 with theadjacent end plate removed;

FIG. 5 is a front side elevation of one of the box frames with theadjacent side plate removed to show the needle end at the left and thedrive gear end at the right;

FIGS. 6A, 6B, 6C and 6D are somewhat schematic end elevations of theneedle end of one of the box frames corresponding to one taken alongline 6-6 of FIG. 2 with the adjacent end plate removed and with thepresser foot operating mechanism omitted, these views showing the lefthead up in A, partly down in B, entirely down in C and partly up in Dand showing the right head (which is the one seen in FIG. 5) down in A,partly up in B, entirely up in C and partly down in D;

FIG. 7 is a fragmentary section corresponding to one taken along line7-7 of FIG. 6A;

FIG. is an end elevation of the needle end of one of the box frames withits corresponding end plate broken away to show the seesaw arrangementfor operating the first and second presser feet in out-of-phaserelationship, this view corresponding to FIG. 6C but omitting the needleoperating mechanism thereof except for the horizontal needle bar and thevertical bar-reciprocating rod;

FIG. 9 is a perspective view of the eccentric reciproeating mechanismfor rocking the seesaw of FIG.

FIG. 10 is a top view of the seesaw rocking mechanism of FIGS. 8-9, thisview corresponding to a horizontal section taken along line lib-10 ofFIG. 8 but omitting the gears and shafts in the gear chamber, crankwheel and needle reciprocating mechanism in reciprocating chamber;

FIG. 11 is a top plan view of a modification utilizing duplicate sewingneedle and presser foot operating mechanisms at each end in each of twoheads, this view omitting the top plate;

3 FIG. 11A is an exploded perspective view of the needle-operating andthread-pull assemblies as seen in the upper right hand corner of FIG.11; and

FIG. 12 is a front-side elevation of the structure seen in FIG. 11, thisview omitting the corresponding side plate of the box frame 30.

DESCRIPTION OF THE PREFERRED EMBODIMENT Conventional Structure The dualhead sewing machine illustrated in the drawing is not entirely old instructural design but, for the sake of simplicity, it is viewed asconventionally comprising: A. an integral stationary base frame; B. atransversely movable A-frame; C. means for transversely reciprocatingthe A-frame; D. material supply means; and E. material feed andtensioning means.

Base Frame The stationary base frame 1, which is skeletonizedthroughout, comprises: (1) an elevated bottom platform frame 2; (2)rear, center and front upright sections 3, 4 and S; (3) a pair ofalleyways including a rear access alleyway 6 located between the rearand center sections 3, 4 and provided with a bottom floor 7, and a frontA-frame-receiving alleyway 8 located between the center and frontsections 4 and S; and (4) two pairs of A-frame supporting tracks 9carried by the under side of the platform frame 2, at each end of thefront alleyway 8, one pair for each end of the A-frame. See FIG. 3.

The transversely movable A-frame 10 comprises: (1) a pair oftransversely spaced upright side standards ll, 12; (2) a pair ofvertically spaced horizontal cross frame members 13, 14 interconnectingthe side standards, one at the top of the A-frame and the other at anintermediate elevation between the top and bottom of the A-frame; and(3) transportation wheels 15 mounted on the side standards to engage theA-frame supporting tracks.

Reciprocating Means The A-frame reciprocating means comprises: (1) arotary cylinder 16 located at the bottom of the front alleyway 8 andmounted on the underlying platform frame 2; (2) an endless zigzag guidetrack 17 encircling and rigidly mounted on the periphery of the cylinder16; (3) a follower 18 on the A-frame depending into driving engagementwith the zigzag guide track 17 on the cylinder 16; and (4) a drive motor19 mounted in the side standard 12 of the A-frame and operativelyconnected to drive the follower 18 so that, through the engagement ofthe follower with the zigzag guide track 17, the follower rotates therotary cylinder 16 and, in doing so, reciprocates the A-frame 10, whichmoves along the front alleyway 8 from right to left and vice versa.

Material Supply, Feed & Tensioning Means The material supply, feed andtensioning means comprises: 1) several rolls of material mounted onsuitable rotary supports including a pair of rotary supports 20, 21 onthe rear section and a rotary support 22 on the center section; 2) apair of rear-tensioning pinch-rolls 23 on the center section 4 along therear side of the upper end or mouth of the front alleyway 8; (3) anotherpair of front-feeding pinch-rolls 24 on the front section along thefront side of the mouth of the front alleyway 8; and (4) a rotarysupport 25 for a rewind roll at the front end of the base frame. Thematerials (from the rolls on the rear section rotary supports 20 and 21)are trained to pass underneath the floor 7 of the rear alleyway 6 andthen pass upwardly to join the material from the roll on the centersection rotary support 22, whereupon all three materials pass forwardly1st through the rear-tensioning pinch-rolls 23, next across the openmouth of the front alleyway 8, during which said materials pass throughthe sewing zone, thence through the front-feeding pinch-rolls 24 andfinally to the rewind roll on support 25.

The foregoing material is fed forwardly by driving the front-feedingpinch-rolls 24 through a train of mechanism 26, which is connected toand driven by the shaft of rotary cylinder 16 of the A-framereciprocating means. To drive the rewind roll support 25 from the shaftof rotary cylinder 16, it is connected to the train of mechanism 26 bybelt 27.

The material, thus fed, is tensioned in the open mouth sewing zonebetween the front and rear pinchrolls 24, 23, by frictionally brakingthe rear pinch-rolls 23 in any suitable yieldable way and therebyyieldably resisting the pull of the front pinch-rolls 24 to a desireddegree, which may be varied by adjusting the frictional brake.

Inventive Structure The dual head structure comprises: A. a box-frame;B. frame-mounted dual heads; and C. a common drive for said heads.

Box-Frame A series of box-frames are located at spaced intervals alongthe space extending transversely between the side standards 11, 12 andvertically betweeen the upper and lower cross frame members 13, 14 ofthe A-frame 10. This series includes: 1) one box-frame 30 at the leftend portion of that space; (2) another box-frame 30 at the right endportion of that space; and (3) as many intermediate box-frames as may bedesirable or necessary, only one intermediate box-frame 30 being shown.

Each box frame 30 has: (1) top and bottom walls; (2) front and rear sidewalls; (3) opposite end walls 31, 32; and (4) between end walls 31 and32, a pair of partitions 33,34 dividng the interior of the box-frameinto a series of3 chambers including (a) a gear" chamber 35 between endwalls 31 and partition 33, (b) an eccentric chamber 36 between the twopartitions 33, 34 and (c) a reciprocating chamber 37 between end wall 32and partition 34. Each box-frame is rigidly secured to the upper crossframe member 13 of the A- frame by bolting its top wall thereto.

Frame Mounted Dual Heads The dual heads include: I) first and secondsewing heads, which are provided in each box-frame and which are locatedon opposite sides of a transverse separating plane P (see FIG. 4)passing vertically through the mid-portion of the box-frames 30; (2)presser foot means; and (3) first and second thread pull means.

Each sewing head conventionally includes: 1 an operating shaft 40extending through the box-frames 30 from gear chamber 35 toreciprocating chamber 37; (2) a needle bar 41 carrying a succession ofneedles;

and (3) motion converting means interconnecting the operating shaft 40with the needle bar 41, this motion converting means comprising (a) acrank wheel 42 located in the reciprocating chamber and mounted on theend of the operating shaft 40 to rotate therewith, (b) a crank or wristpin 43 mounted on wheel 42 but offset from the center thereof to providea crank arm of desired length, (c) a link or pitman 44 interconnectingthe crank pin 43 with a vertically reciprocating pin 45 which extendshorizontally through a vertical slot, by the walls of which it is guidedin vertical reciprocating motion, and (d) rod 46 for supporting theneedle bar 41 from the reciprocating pin 45. Each sewing head alsoincludes conventional thread locking mechanism (not shown) housed in thelower cross frame member 14 and positively driven by motor 19 in timedrelationship with the needles on needle bar 41.

The presser foot means conventionally includes: (1) first and secondpresser-foot bars 51; and (2) unconventional motion converting meansinterconnecting one operating shaft 40 with the presser-foot bar 51 (seeFIG. 8) in accordance with one feature of this invention. Thisunconventional means comprises: (a) a rockshaft 52 mounted on thepartition walls 33, 34 to extend through the eccentric and reciprocatingchambers 36, 37; (b) means for rocking the rock shaft 52, said meansincluding a rock arm 53 located in eccentric chamber 36 and mounted onrockshaft 52, and means interconnecting only one of the two operatingshafts 40 with. rock arm 53 to rock the rockshaft 52, saidinterconnecting means including (see FIG. 9) a rotating eccentric 54encircling and mounted on operating shaft 40 torotate therewith, anon-rotating circular collar 55 encircling the eccentric, and a link 56interconnecting the collar 55 with the outer end of the rockshaft arm 53on rock shaft. 52; and (c) means converting said rocking movement ofrock shaft 52 into vertical reciprocating movement, such means including(see FIG. 8) a teeter-totter 57 mounted on rockshaft 52 within thereciprocating chamber, and first and second vertical rods 58, 59interconnecting opposite ends of the teetertotter 57 with said first andsecond presser-foot bars 51. It will be understood that, while I preferthe use of a teeter-totter or its equivalent to reciprocate the firstand second presser-foot bars 51 in 180 out-of-phase relationship, myinvention also contemplates the use of other interconnecting means foreffecting the reciprocation in l800 out-of-phase relationship. Thisincludes separate and independent means conventionally constructed tointerconnect first and second bars with first and second operatingshafts for reciprocating purposes but unconventionally arranged forout-of-phase purposes.

Each of the first and second thread pull means may be conventionalexcept for an adjustment feature. Each thread pull means includes: (1) arigid orbital pin-link unit composed of (a) said crank pin 43, which isrigidly mounted on crank wheel 42 to project from an end face thereoffor orbiting purposes and (b) a link 62 rigidly mounted at one end ofsaid projecting orbital crank pin 43; (2) a somewhat L-shaped threadpull lever 63 pivotally mounted on the outer end of said link 62 withits opposite end 64 available for thread pull purposes; and (3) a guidelever 65 pivoted at one end to a fixed post 66 on said box-framepartition 34 and pivotally connected at its opposite end tothemid-portion of said guide lever 65 for guiding purposes.

In accordance with a particular feature of my invention, the pull lever63 on the thread can be advanced or retarded by angularly turning theorbiting pin-link unit, one Way or another, about the axis of itsorbital crank pin 43 from one position to another and securing it in itsturned or adjusted position. To this end, the orbital crank pin 43 isrigidly mounted on crank wheel 42 to project from the end face thereof.It is fixed in its desired position by a set screw 67. This adjustmenteffect an advance or delay in the thread pulling function of the threadbar.

Common Drive For Dual Heads In accordance with one important feature ofmy invention, both heads are driven by a common drive which includes:(1) a main drive shaft; and (2) gear means connecting the main driveshaft to the first and second operating shafts 40.

The main drive shaft 70 extends transversely across the machine from thelarge A-frame side standard 12. Within standard 12, it is connected inany conventional or other suitable manner to the main drive motor 19.

'- In extending across the machine from standard 12,

shaft passes entirely through the first two boxframes 30 and terminateswithin the gear chamber 35 of the third and last box-frame.

The gear means located in the gear chamber 35 of the first box-frame isreproduced in each of the other gear chambers 35 of the remainingbox-frames. Each gear means comprises: (1) a main drive gear 71 mountedon the main drive shaft 70; and 2) first and second driven gears 72, 73respectively mounted on the first and second operating shafts 40 of thefirst and second sewing heads and connected thereto in a manner causingthe first operating shaft to rotate in the same direction as the maindirve shaft70 and the second operating shaft 40 to rotate in the reversedirection. To this end, the driven gear 73 on the second operating shaftis arranged to mesh with the main drive gear 71 on the main drive shaft70 while the driven gear 72 on the 1st operating shaft 40 is connectedto themain drive gear 71 through an idler 74.

Operation Since the operation of the sewing machine will be clear fromthe foregoing, it should suffice to say: (1) that, when energized, motor19 (a) drives the front feed rolls 24 and the rewind roll 25 formaterial feeding and rewinding purposes, (b) reciprocates the A-frame10, (c) drives the dual heads in a positive manner and in out-of-phaserelationship to reciprocate both needle bars 41, both presser-foot bars51 and both thread pull levers 63 and (d) rotates the thread lockingmechanism in the lower A-frame cross frame member 14. As a result: (a)the material is fed forwardly through the machine more or lessconstantly although the movement of that material at and through thesewing zone is momentarily stopped in a conventional manner bypresser-foot engagement; (b) the main drive shaft 70 rotatescontinuously; (c) the positively driven first and second operatingshafts 40 of the sewing heads rotate continuously but in oppositedirections and in 180 out-of-phase relationship; (d) the first andsecond needle bars 41 reciprocate continuously in a positive manner andin an 180 out-of-phase relationship to effeet the sewing of straight orzigzag lines which are laterally spaced and longitudinally parallel; (e)the first and second resser-foot bars reciprocate continuously in apositive manner (with a slight dwell period during the lower end portionof each downward stroke) and do so in l80 out-of-phase relationship; and1st and 2nd thread guide levers 65 jerk up and move down in l80out-of-phase relationship with each lever being adjustable to advance orretard the beginning of its particular thread jerking action.

Modification The preferred embodiment of FIGS. luses single first andsecond needle bars 41 and presser-foot bars 51 for all three of thebox-frames and for all three of the first and second dual heads on suchbox-frames. My invention, however, contemplates the use of separateindividual needle and presser-foot bars and four barsupporting rods foreach head of each separate boxframe. A modified construction of thischaracter is illustrated in FIGS. 11, 11A and 12.

In this modification, the first gear chamber 35 of each box-frame isused as an additional reciprocating chamber while the positive commondrive for the dual heads is slightly modified and transferred to theeccentric chamber 36. Since the space of eccentric chamber 36 islimited, the common drive is modified: (l) by placing the main drivegear 71 on the main drive shaft 70 in mesh with the driven gear on oneof the operating shafts, in this case the first driven gear 72 on the1st operating shaft 40 whereby shafts 70 and 40 rotate in oppositedirections; (2) by eliminating the second drive gear from the secondoperating shaft 40; and (3) by driving the second operating shaft 40from (and in the same direction as) the main drive shaft 70 through adrive train comprising a sprocket 80 on the main drive shaft 70, asprocket 81 on the 2nd operating shaft 40, and a chain (not shown)interconnecting the two, the chain also engaging an intermediate idler82, which can be adjustably positioned for chain-tensioning purposes.

The rock shaft 52', (which, in the embodiment of FIGS. 1-10, extendsfrom the second chamber of the box-frame into the third chamberthereof,) is now extended into the 1st chamber of each box-frame and aduplicate, of the sewing head, presser-foot and thread pull mechanisms,is installed within the first chamber of each box-frame 30. Thisduplicate carries one vertically-arranged pair of first and second(needle-bar) reciprocating rods 46 and one vertically-arranged pair of1st and 2nd (presser-foot-bar) reciprocating rods 58, 59, which dependfrom within each end of each box-frame 30 downwardly into supportingengagement respectively with the corresponding ends of one pair of shortfirst and second needle bars 41 and of one pair of short first andsecond presser-foot bars 51. In other words, each short needle bar 41'and presser-foot bar 51', for a given box-frame, is supported at each ofits opposite ends by reciprocating rods depending from said givenbox-frame.

It will be understood that my invention contemplates the out-of-phaserotation of both rockshafts 40 in the same direction because in suchoperation, a significant amount of counter-balancing should occur. Iprefer reverse 180 out-of-phase rotation because the maximum amount ofcounter-balancing will occur.

Having described my invention, I claim:

1. Dual sewing heads for a multi-needle machine of the type sewing aseries of long straight or zigzag lines of stitching into elongatesuperposed strips of bedding material passing through the machine,comprising:

A. substantiallyv identical first and second sewing heads, one on eachside of a vertically arranged transverse plane, said first and secondsewing heads including 1. a frame, and 2. corresponding first and seconda. frame-mounted multi-needle bars, and b. frame-mounted means forpositively reciprocating said multi-needle bars vertically; and

B. a common drive means for positively driving both sewing heads in asubstantially fixed phase relationship.

2. The dual heads of claim 1 wherein:

A. said common means includes 1. first and second rotary shafts, and 2.means for rotating said shafts in opposite directions.

3. The dual heads of claim 2 wherein:

A. said common drive means is connected to drive said sewing heads inout-of-phase relationship.

4. The dual heads of claim 2 wherein:

A. said first and second sewing heads include corresponding first andsecond I. frame-mounted presser-foot bars, and 2. frame-mounted meansfor positively reciprocating said presser-foot bars vertically; and

B. said common drive means is connected to drive said presserfoot barsin 180 out-of-phase relationship but with the reciprocations of eachpresserfoot bar being operatively coordinated with the reciprocations ofits corresponding needle bar.

5. The dual heads of claim 1 wherein:

A. the 1st sewing head includes a first horizontal frame-mounted rotarydrive shaft between the first multi-needle bar and said common drivemeans; and

B. said dual heads include presser-foot means composed of l. first andsecond presser-foot bars, one on each side of said plane,

2. a rockshaft in said plane,

3. motion converting means interconnecting said first drive shaft andsaid rockshaft to convert the rotary motion of the first shaft intorockshaft rocking movement, and

4. a teeter-totter mounted on said rockshaft to rock therewith andoperative, when rocked, to reciprocate said first and secondpresser-foot bars in 180" out-of-phase relationship.

6. The dual heads of claim 1 wherein:

A. the first sewing head includes a 1st horizontal frame-mounted rotarydrive shaft in the drive connection between the first multi-needle barand said common drive means,

1. said 1st shaft having a crank wheel; and

B. said first head has a first thread pulling means,

which includes 1. a wrist pin offset from the axis of said crank wheeland mounted thereon to project from an end face thereof,

2. a radial link rigidly mounted on the projecting portion of said wristpin and cooperating therewith to provide a rigid pin-link unit,

9 10 3. a thread pull lever pivotally mounted at one end meanssubstantially identical to the first; and

on an outer end portion of said radial link and ar- C. said common drivemeans is connected to drive ranged at its opposite end to engage thesewing said first and second thread pullmeans in a subthread for threadpulling purposes, stantially fixed phase relationship which is coordi-4. a guide lever pivoted at one end to said frame nated to thereciprocations of the corresponding and at its opposite end to themid-portion of said multi-needle bars. thread pull lever for guidingpurposes, and 8. The dual heads of claim 7 wherein: 5. means foradjusting the angular position of said A. said common means includesrigid pin-link unit one way or the other on said 1. first and secondrotary shafts, and crank wheel so as to advance or retard the time 10 2.means for rotating said shafts inopposite direcat which said pull leverexerts a pull on said tions. thread. 9. The dual heads of claim 8wherein: 7. The dual heads of claim 6 wherein: A. said common drivemeans is connected to drive A. the second sewing head has a secondrotary driv said first and second sewing heads in 180 shaftsubstantially identical to the first; outof-phase relationship.

i i I i i B. said second head has a second thread pulling

1. Dual sewing heads for a multi-needle machine of the type sewing aseries of long straight or zigzag lines of stitching into elongatesuperposed strips of bedding material passing through the machine,comprising: A. substantially identical first and second sewing heads,one on each side of a vertically arranged transverse plane, said firstand second sewing heads including
 1. a frame, and
 2. corresponding firstand second a. frame-mounted multi-needle bars, and b. frame-mountedmeans for positively reciprocating said multi-needle bars vertically;and B. a common drive means for positively driving both sewing heads ina substantially fixed phase relationship.
 2. corresponding first andsecond a. frame-mounted multi-needle bars, and b. frame-mounted meansfor positively reciprocating said multi-needle bars vertically; and B. acommon drive means for positively driving both sewing heads in asubstantially fixed phase relationship.
 2. The dual heads of claim 1wherein: A. said common means includes
 2. means for rotating said shaftsin opposite directions.
 2. a rockshaft in said plane,
 2. frame-mountedmeans for positively reciprocating said presser-foot bars vertically;and B. said common drive means is connected to drive said presserfootbars in 180* out-of-phase relationship but with the reciprocations ofeach presser-foot bar being operatively coordinated with thereciprocations of its corresponding needle bar.
 2. means for rotatingsaid shafts in opposite directions.
 2. a radial link rigidly mounted onthe projecting portion of said wrist pin and cooperating therewith toprovide a rigid pin-link unit,
 3. motion converting meansinterconnecting said first drive shaft and said rockshaft to convert therotary motion of the first shaft into rockshaft rocking movement, and 3.The dual heads of claim 2 wherein: A. said common drive means isconnected to drive said sewing heads in 180* out-of-phase relationship.3. a thread pull lever pivotally mounted at one end on an outer endportion of said radial link and arranged at its opposite end to engagethe sewing thread for thread pulling purposes,
 4. The dual heads ofclaim 2 wherein: A. said first and second sewing heads includecorresponding first and second
 4. a teeter-totter mounted on saidrockshaft to rock therewith and operative, when rocked, to reciprocatesaid first and second presser-foot bars in 180* out-of-phaserelationship.
 4. a guide lever pivoted at one end to said frame and atits opposite end to the mid-portion of said thread pull lever forguiding purposes, and
 5. means for adjusting the angular position ofsaid rigid pin-link unit one way or the other on said crank wheel so asto advance or retard the time at which said pull lever exerts a pull onsaid thread.
 5. The dual heads of claim 1 wherein: A. the 1st sewinghead includes a first horizontal frame-mounted rotary drive shaftbetween the first multi-needle bar and said common drive means; and B.said dual heads include presser-foot means composed of
 6. The dual headsof claim 1 wherein: A. the first sewing head includes a 1st horizontalframe-mounted rotary drive shaft in the drive connection between thefirst multi-needle bar and said common drive means,
 7. The dual heads ofclaim 6 wherein: A. the second sewing head has a second rotary driveshaft substantially identical to the first; B. said second head has asecond thread pulling means substantially identical to the first; and C.said common drive means is connected to drive said first and secondthread pull means in a substantially fixed phase relationship which iscoordinated to the reciprocations of the corresponding multi-needlebars.
 8. The dual heads of claim 7 wherein: A. said common meansincludes
 9. The dual heads of claim 8 wherein: A. said common drivemeans is connected to drive said first and second sewing heads in 180*out-of-phase relationship.